Medical Device with Elastomeric Bulb

ABSTRACT

A drainage catheter including a body, a drainage lumen extending between the body proximal end and the body distal end, the drainage lumen including a distal fluid inflow port and a proximal fluid drain coupling, and an inflation lumen extending between the body proximal end and the body distal end, conveying inflating fluid from a proximal fluid supply element to a distal fluid acceptor balloon, the proximal fluid supply element adjacent the proximal fluid drain coupling. A sleeve may be secured about the proximal fluid supply element and the proximal fluid drain coupling to provide a fluid impervious coating.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/009,749, filed Jan. 19, 2011, now U.S. Pat. No. 8,241,247, which is acontinuation of U.S. patent application Ser. No. 11/289,124, filed Nov.29, 2005, now U.S. Pat. No. 7,875,003, which is a division of U.S.patent application Ser. No. 09/720,309, filed Apr. 9, 2001, now U.S.Pat. No. 6,979,313, which is a U.S. national stage application under 35USC §371 of International Application No. PCT/EP99/04421, filed Jun. 25,1999, which claims priority to International Application No.PCT/EP98/03892, filed Jun. 25, 1998, each of which aforementionedapplication is incorporated by reference in its entirety into thisapplication.

TECHNICAL FIELD

A pre-filled Foley catheter can be regarded as one example of a medicaldevice with a proximal end and a distal end, an elastomeric bulb at theproximal end for storing fluid under pressure and a fluid acceptor atthe distal end and a lumen connecting the bulb and the acceptor for flowof fluid from the bulb to the acceptor when the device is used, andincluding a control device at the proximal end of the lumen to preventsaid fluid flow until said flow is desired. It is in this class ofmedical devices that the present invention is to be found.

BACKGROUND

The Foley catheter is a catheter device usually made out of elastomericmaterial, which is for urine drainage and which is installed with itsdistal end in the bladder of the patient. When the distal end of thecatheter has been advanced into the bladder, sterile water is caused toflow along a lumen from the proximal to the distal end of the catheter,there to fill a balloon at the distal end of the catheter. This balloonretains the distal end of the catheter in the bladder and allows asecond lumen in the catheter shaft, open to the bladder at the distalend of the shaft, to drain urine from the bladder to the proximal end ofthe catheter.

In a pre-filled Foley catheter, the device includes a reservoir ofsterile water in the proximal end of the device, and a clip over theshaft of the catheter at its proximal end, which clip prevents thesterile water from flowing from the distended reservoir bulb along thelumen to the distal end of the catheter. The person placing the catheteris required to hold the catheter in the desired disposition relative tothe body of the patient, and then remove the clip and squeeze thereservoir bulb, in order to inflate the balloon. It would be desirableto provide an improved device for preventing fluid flow from thereservoir to the balloon until it is desired to do so. U.S. Pat. Nos.3,275,001 and 3,675,658 disclose the use of internal plugs instead ofclips.

Achievement of a satisfactory shelf-life for pre-filled Foley cathetershas proved to be a challenge. Common elastomeric material, such aslatex, is not entirely impermeable to the passage of water. Accordingly,the water in the distended bulb reservoir of elastomeric material canescape through the wall, given enough time. In order to achieve asatisfactory shelf-life (18 to 24 months) it has been proposed to coverthe outside of the reservoir bulb with a coating of material moreresistant to passage of water than latex. Nevertheless, residualproblems remain, some of which are discussed in U.S. Pat. No. 3,602,226.

One such problem is that the coating tends to crack. This reduces theresistance to escape of water and can adversely affect appearance.Another problem is to achieve satisfactory continuity of the coatingaround the clip at the distal end of the bulb, and the customary fillervalve at the proximal end of the bulb. Even then, there is potential forwater to escape from the bulb by flowing lengthways along theelastomeric material of the wall of the bulb, until it has passed thedistal and proximal ends of the waterproof coating material.

The thickness of latex catheters made by a conventional dipping processis always liable to vary, and this variation can prejudice the goal ofreliable sealing with an external moulded clip. With a conventionalU-shaped one-piece clip, and latex walls of uncertain thickness, thereis some potential for the clip to damage the latex lumen wall.

SUMMARY OF THE INVENTION

The invention may be incorporated in embodiments that may include one ormore of the following objects, features and characteristics.

An object of the present invention is to achieve greater certainty,during the manufacture of pre-filled Foley catheters, that the catheterwill deliver a satisfactory shelf life.

A further object of the present invention is to provide a pre-filledcatheter which lends itself to easy actuation, with a singlemanipulation (like removal of the conventional clip) being sufficient toachieve the result that all fluid in the reservoir flows to the distalend balloon cavity.

Another object of the invention is to improve the design of the catheterso that its manufacture is streamlined, its packaging and storage mademore compact and reliable, and its appearance made more attractive.

Thus, in accordance with a first aspect of the present invention, thereis provided a medical device of the type identified above, and which ischaracterised in that said control device comprises a plug which blocksthe lumen at its proximal end and includes a parting line, which enablesthe plug to be parted into two separate parts, by manual manipulationfrom outside the lumen, such parting having the effect of opening upfluid communication along the lumen from the elastomeric bulb to theballoon to fill the balloon.

Advantageously, once the plug is parted, there is no need for the personinstalling the catheter to manipulate any longer the plug or lumen.

Additionally the stress distribution in the wall of the bulb at the neckat its distal end is much more uniform with a plug than with thecustomary clip. An enhanced ability to predict patterns of stress andstrain at the balloon neck should in turn allow better waterproofing inthe distal neck region.

Moreover, provision of a parting line avoids the need to disturb theinterface between plug and lumen. This is especially advantageous withlatex lumens, or other lumens created by dipping, in which the wallthickness varies, because actuation of the control device need notinvolve any surface in contact with the lumen wall. Where the lumen wallthickness varies, so will the elastic performance, and when the elasticperformance varies, there will be unpredictability in the manipulationof any surfaces constrained elastically by the lumen wall surface.

Conventionally, a Foley catheter of latex is molded with a narrow lumen(of the order of 0.8 mm diameter) and a proximal bulb inner diametermuch larger. Thus, in another aspect of the invention, the distal neckof the bulb cavity can be molded to correspond in shape with the distalend of the plug. These complementary surfaces prevent excessive advanceof the plug distally beyond the bulb neck.

Stabilisation of the interface between the lumen wall and the surfacesof the control device makes it easier to render the bulb fluid-tight inthis interface zone. The medical device is much easier to pack and tohandle in the terminal stages of manufacture because it lacks the bulkof an external clip.

Conventional external clips become separated from the conventionalpre-filled Foley catheter, once the catheter has been installed, and onethen has the task of disposing of the loose clip. With the device of theinvention, the component parts of the control device are retained withinthe bulb.

One-handed operation of the valve requires less manual dexterity thanwith an external clip which has to be removed. Snapping of the plug intotwo pieces provides a tactile signal that the fluid passage has beenopened up. With opaque lumen material, such as latex, the plug cannot beseen, so such a tactile signal is especially valuable with opaquematerials.

In another aspect of the invention, the use of the plug facilitatesavoidance of potential difficulties in coating the interior of thereservoir, as may be desired to waterproof the reservoir to minimizeliquid loss during storage. By placement of a plug in the distal neck ofthe bulb, before the coating process the coating material will beprecluded from blocking the lumen. A coating of proofing material on theexternal surface of the plug ought not to have any adverse effect on theoperation of the plug device.

In another embodiment, it is envisaged that the plug device might carrywith it a skirt or cylinder of waterproof material, to serve as thefluid-resistant wall of the bulb, or an inner waterproof surface coatingof the wall of the bulb, the skirt or cylinder being gathered at theproximal end of the bulb, and fitted around the customary bulb fillervalve. Cakes are decorated using an icing sugar mixture which isextruded through an icing nozzle, itself set in the neck of an icingbag. The other end of the bag is held closed by the hand of the user.The contemplated arrangement of plug and skirt might resemble anarrangement of icing nozzle and icing bag, with the filler valve closingthe end of the skirt remote from the plug.

The control of flow of fluid in a lumen, using a device in the lumenwhich is separable into two parts in order to allow fluid flow, is notin itself new. Such an arrangement is disclosed in, for example,GB-A-1573482 and U.S. Pat. No. 4,007,738 published Feb. 15, 1977. It isto be noted, however, that the proposal of the present invention allowsthe control device to be placed such that it extends proximally into theinterior of the bulb.

This provides more room for displacement of one part of the controldevice relative to the other, and for eliminating elastic stresses in alumen wall which might otherwise act to bring the two displaced parts ofthe control device back into their original sealing disposition relativeto each other. Depending on the materials used and the dimensions of theplug and lumen walls, locating the control device partly within the bulbmay assist in delivering many of the attractive technical effects of thepresent invention.

In a further aspect the present invention provides a medical devicewhich is a drainage catheter having first and second lumens, with thefirst lumen serving as a drainage lumen and having a fluid inflow portat its distal end and a fluid drain coupling at its proximal end. Thesecond lumen serves to convey inflating fluid from a fluid supplyelement at the proximal end of the device to a fluid acceptor balloon atthe distal end. The fluid supply element and fluid drain coupling arearranged side by side at the proximal end of the coupling, and thedevice is characterised by a sleeve which extends around both the fluiddrain coupling and the fluid supply element.

Normally, the fluid supply element will be an elastomeric bulb which isdestined to be inflated with the inflating fluid. In that case, thesleeve would be of a material which is more impervious to the inflatingfluid than is the elastomeric material of the bulb, so that the presenceof the sleeve has the effect of slowing the rate of loss of fluidradially outwardly from the bulb through the wall thickness of the bulb.

Although this is the normal situation, it is envisaged that theprovision of a sleeve around both the fluid drain coupling and the fluidsupply element could have other advantages independent of reducing fluidloss during storage of a pre-filled device. For example, in the casewhere the device is made of material which does not readily acceptprinted text, or in a case where it is desired that there should be noprinted text on the device as such, the sleeve material could beselected as suitable for use as a printing substrate, and could receiveprinted matter which serves to inform those handling the device, untilsuch time as the device is put into use, at which point the sleeve wouldbe removed.

It is particularly envisaged that the technical feature of a sleeve,which characterises the second aspect of the invention, is used incombination with the technical feature of a lumen plug which parts intotwo pieces, characteristic of the first aspect of the invention. Inparticular, a urinary drainage catheter, such as a Foley catheter, whichincorporates a reservoir pre-filled with liquid to inflate the distalbulb of the catheter, and which is made, as conventionally, with latexrubber material, benefits from an enhanced shelf life both by theprovision of a sleeve around the reservoir bulb at the proximal end ofthe catheter, and the provision of a plug instead of a conventionalexternal lumen clip, because the sleeve over the bulb works moreeffectively when there is no clip on the external surface of thecatheter adjacent the reservoir bulb. This is because it is easier toarrange the sleeve for full effectiveness when the surface it covers iswithout discontinuities, and when the sleeve is not subject to localisedstresses caused by the external clip.

In this way, the sleeve and plug work together to enhance the shelf lifeof the device.

In this connection, inclusion of the fluid drain coupling alongside thefluid supply element inside the sleeve will not appreciably reduce theeffectiveness of the sleeve in slowing down the rate of loss of fluidthrough the wall of the reservoir bulb. This is because both elementscan be made with surface topographies made up of gentle curves and outof relatively soft materials which therefore deform relatively easily toconform to the embrace of a sleeve applied using shrink wrappingtechniques. However, placing the sleeve around both the fluid draincoupling and the fluid supply element can deliver the technical effectthat the device is packed in a more compact and orderly way, whichfacilitates further manufacturing processing and packaging of thedevice, and improves the visual attractiveness of the devide to thosewho purchase and use it. It also provides a packaging over the fluiddrain coupling (which in present devices is not sleeved) and a vehiclefor carrying printed matter.

Both aspects of the invention are particularly applicable to medicaldevices made of latex rubber, especially urine drainage catheters madeof latex rubber. However, both aspects of the invention will also beuseful with devices made of other materials. One of these may besilicone rubber, an alternative material for urine drainage catheters.

Normally, the fluid received at the distal end of the catheter will bewater, that is, sterile water, but the invention is not restricted tofluids which are liquids. Fluids which are gases may also be ofinterest.

The plug control device is conveniently formed as an annulus of materialwith a proximal end face and a distal end face and a bore extendingbetween the two end faces. Coaxial with the annulus is a stem, blockingthe bore in the annulus, until the plug is parted into two separateparts, these two separate parts being the annulus and the stem.Conveniently, the plug is formed of synthetic polymeric material,injection moulded as a single component, with a circle of weakness,constituting the parting line, between the annulus and the stem, at oneend of the bore through the annulus. However, it can also be envisagedthat the plug is formed of two components, the annulus and the stem, puttogether as the plug is installed in the lumen, and parted into therespective annulus and stem components, along the parting line where thetwo components abut one another, when the stem is manipulated fromoutside the device. In such a case, the stem might be friction fittedwithin the bore of the annulus.

Normally the stem is cylindrical and has a diameter not more than abouthalf that of the plug at its widest point. Advantageously, the stem isnot more than one third the plug diameter. In one example, the stem is2.25 mm diameter and the plug at its widest is 7.5 mm in diameter. Thisleaves plenty of room around the stem to engage the stem with aninjector rod to position the plug in the lumen.

Normally, the plug is advanced into the lumen from the proximal end ofthe lumen with its stem directed rearwardly. Normally, the open proximalend of the lumen is closed by a filler valve, and the plug is spacedsome way from the filler valve, distally along the lumen. The lumenlength between the filler valve and the plug contains the cavity forstoring fluid under pressure, that is to say, the fluid supply elementand elastomeric bulb of preferred embodiments of the present invention.Fluid is introduced through the filler valve into the lumen cavitybetween the filler valve and the plug, to inflate the elastomeric bulbbetween the valve and the plug. The valve is a check valve (not unlikeone on a bicycle tire) which resists reverse flow of the fluid in thebulb. In these respects, the reader will be informed by conventionalpractice in the technical field of urine drainage catheters,particularly Foley catheters. Variations of construction of the fillervalve are not in themselves an aspect of the subject matter of thepresent invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, and to show moreclearly how the same made be carried into effect, reference will now bemade, to the accompanying drawings, in which;

FIG. 1 is a longitudinal diametral section through a Foley catheterwhich is within the state of the art;

FIG. 2 is a longitudinal diametral section through a Foley catheter inaccordance with the present invention; and

FIG. 3 is a longitudinal diametral section through the proximal end ofthe FIG. 2 catheter, showing the plug parted into two parts;

FIG. 4 is a longitudinal diametral section of a catheter in accordancewith FIG. 2, showing a sleeve extending around both the fluid draincoupling and the fluid supply element;

FIG. 5 is a longitudinal section, similar to that of FIG. 4, but showinga sleeve which extends only around the fluid supply element, and notaround the fluid drain coupling;

FIG. 6 is a longitudinal section through apparatus for placing the pluginside the lumen of the Foley catheter; and

FIG. 7 is a section like FIG. 6, but showing the plug after placement inthe lumen.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a known pre-filled Foley catheter. The catheter 10comprises a shaft 11 of latex rubber which defines a balloon inflationlumen 12 and a drainage lumen 13. The drainage lumen 13 extends from adistal drainage port 14 to a drainage bag coupling element 15 at theproximal end of the catheter. The inflation lumen 12 connects a chamber20 at the distal end of the catheter, but proximal of the drainage port14, with a reservoir bulb 21 at the proximal end of the device. In FIG.1, both of the balloon 20 and bulb 21 are shown inflated, for the sakeof clarity, but those skilled in the art will appreciate that thesterile water within the bulb 21 is not sufficient simultaneously tofill both the bulb and the balloon. The reality is that, when the bulb21 is full, the balloon 20 is not yet inflated and, when the balloon 20is fully inflated, the bulb 21 is deflated.

The bulb 21 has a proximal end 22 and a distal end 23. At the proximalend 22 is a conventional one-way filler valve 24 with which thoseskilled in the art will already be familiar. At the distal neck 23 ofthe bulb 21, there is a conventional external clip E to clamp togetherthe walls of the lumen 12.

Turning to FIG. 2, the catheter shown in this drawing figure isidentical to that of the FIG. 1 catheter, except that the external clipE has been replaced, in accordance with the invention, by a plug 25which is a friction fit inside the lumen 12, the plug 25 beingintroduced distally into the lumen 12 through the interior of the-bulb21 and, in so doing, elastically deforming the material of the shaft 11of the catheter 10. FIG. 3 shows in more detail the construction of thiscontrol device.

In FIG. 3 the control device can be seen to be made up of a tapered plugportion 26 and a solid stem portion 27 which occludes the proximal end28 of a bore 29 which extends completely through the plug portion 26, asfar as its distal end 30. The solid stem 27 is integral with the plugportion 26, but joined to it by a narrow and weak circle 31 of materialaround the proximal end 28 of the bore 29. The circle 31 constitutes aparting line.

The tapered portion 26 is itself made up of adjacent more or lessfrusto-conical portions. The larger frusto-conical portion 26 a has arelatively gentle taper along the plug axis, and the smallerfrusto-conical portion 26 b has a relatively faster steeper taper,together giving the plug a rounded bullet nose to be advanced along thelumen to the desire location. There is a step 26 c between the taperedportion of the plug and its cylindrical portion 26 d of largestdiameter.

The length of the large diameter cylindrical portion 26 d is preferablysmaller than its radius, thereby enhancing lumen sealing around thisportion of the plug. The length of the plug annulus is preferablygreater than its maximum diameter, which helps to keep the plug pointingin the axial direction as it is pushed from behind to advance along thelumen.

The control device is formed from synthetic polymeric material which isselected so that manual manipulation of the solid stem 27 relative tothe plug portion 26 is quite sufficient to tear the polymer material ata point on the circumference of the weak circle 31, thereby allowing thestem 27 to rotate relative to the plug portion 26, with further tearingof the material around the circle 31 putting in fluid communication thebulb 21 surrounding the stem 27 with the bore 29 through the length ofthe plug portion 26.

Because of the softness of the bulb, and the open space between the wallsurfaces of the bulb 21 surrounding the stem 27, there is great scopefor manual manipulation of the bulb, from outside it, to achieve a largeangle of rotation of the stem 27 relative to the plug portion 26, withconsequent great certainty of putting the bulb 21 in communication withthe bore 29. Nevertheless, the stem 27 may lie in the lumen 12 spacedfrom the bulb, if the lumen is susceptible enough to externalmanipulation and bending to permit the stem 27 to be snapped away fromthe annulus 26.

Those skilled in the art will be familiar with the conventionaldimensions of a pre-filled Foley catheter. Of course, many of these aredetermined by the dimensions of the associated parts of the human body.The researches of the present applicant, as to what are the preferreddimensions of the plug control device, have resulted in a proposal thatthe control device should be constructed in accordance with thefollowing scheme of dimensions (all in mm): the stem portion 27 has alength of 10 and a diameter of 2.25;. the plug portion has a length of 9and a bore diameter of 2; the frusto-conical outer diameter range isfrom 5.5. to 4.3; there is a transition zone from the proximal end ofthe 2 mm axial bore of the plug portion, to the 2.25 mm diameter circleon the proximal end face of the plug portion, which extends distallyfrom the proximal end face over a distance of 0.625 mm.

The bulb can be water-proofed (as is known) for example by dipping inSaran® a polyvinylidene chloride coating composition. Otherwise it couldbe water-proofed by, e.g. dipping or spraying it with silicone, neoprenerubber, butyl rubber or hydrophobic polyurethane. Those skilled in theart will be aware of such procedures and practices.

One suitable polymer material for the plug device is polyvinylchloride.However, there is currently prejudice against the use of PVC. Highimpact polystyrene is another possibility. A polyester material such aspolybutyleneterephthalate may be worthy of consideration.Styreneacrylonitrile is another polymer of particular interest. Theselection of polymers for medical applications is a field in which thereis considerable experience. Some special factors apply, for example,gamma ray sterilisation is usual, and the polymer must obviously be ableto withstand all production process steps, including sterilisation, aswell as being stable enough to survive the required shelf life period inthe environment in which it finds itself. Resistance to solvents,possibly acetone, may be another significant factor. Putting the bulbinterior in communication with the tube should not result in any loosefragments of the control device, especially not any transport of suchfragments to the fluid acceptor. Accordingly, the preferred failure modebetween stem portion 27 and plug portion 26 is tearing.

Although the presently preferred embodiment involves a circle ofweakness, and parting of the polymer material around the weakness circle31, nevertheless it is contemplated that alternative embodiments may bedesirable in which, for example, the stem portion 27 is not integralwith the plug portion 26 but, rather, is a separate piece which isfriction fitted with the proximal end 28 of the bore 29. If this werethe case, then it might be appropriate to provide stepped or taperedportions of the proximal end of the bore 29 or the distal end of thestem 27.

Although the present invention arose out of a consideration of how toimprove a specific product, the pre-filled Foley catheter, neverthelessthe concept of the invention might be applicable elsewhere. Inparticular, the interaction of a plug stopper and a distendedelastomeric reservoir of sterile fluid could be useful whenever there isneed for a supply of sterile fluid from a bulb. Thus, it could bearranged that, while the plug remains intact, the fluid is safe andsterile within the bulb, and resistant to damage or decay but, upon asimple manipulation of the stem of the plug, a supply of sterile fluidis available, from the bulb, in whatever quantities and rate of flow areselected by the user, by varying the squeezing and manipulation of theelastomeric bulb.

FIGS. 4 and 5 illustrate alternatives, in accordance with the secondaspect of the present invention, to coating the fluid supply element atthe proximal end of the device. Instead of dipping the proximal end in acoating liquid, the proximal end is surrounded by a sleeve. This sleevecan be like the sleeve 40 of FIG. 4, embracing both the bulb 21 and thecoupling element 15, or like the sleeve 42 of FIG. 5, embracing only thebulb 21 and not the coupling 15.

One way of providing the sleeve is to use stretchy material, pre-formedas a sleeve. The lumen 11 could be advanced through the sleeve, and thenthe sleeve restrained while the distal parts of the catheter are pulledthrough the sleeve, until the sleeve is stretched by the structures atthe proximal end of the catheter and ends up stretched over the bulb 21and bag connector 15, as shown in FIG. 4.

However, it is presently preferred by Applicant to pre-form the sleevefrom shrink wrap material, which is 50 um thick oriented polystyrenematerial. Such material, somewhat thinner, say 40 um thick, is also seenas likely to be suitable and useful. For the conventional Foleycatheters which Applicant makes, it is appropriate to use a pre-formedtube which, when flat, has a width of 45 mm and which, for use in thepresent invention, is cut into lengths of 90 mm, this being long enoughto extend over not only the bulb 21 but also the fluid control device 25and the distal end of the filler valve 24, as shown in FIGS. 4 and 5.Preferred is shrink wrap sleeving which includes a tear strip or tabincorporated along its length. In the particular embodiment favoured atpresent by applicant, this tear tab has a width of 10 mm.

Shrink wrap sleeving, of the description immediately above, is availablefrom Decorative Sleeves Ltd, Hardwick Industrial Estate, Kings Lynn,Norfolk, England.

Although a tear tab is not essential, and although the precise locationof the tear tab relative to the drain coupling 15 and fluid bulb 21 isnot critically important, it is presently preferred to locate the tearstrip to lie over the surface of the bulb 21, diametrically oppositefrom the location of the drain coupling 15.

Those skilled in the art will be familiar with techniques for printingon polystyrene film. Should it be desired, printed matter can be placedon the polystyrene tubing pre-form, before the sleeve is placed over thebulb of the catheter.

As can be seen in FIGS. 4 and 5, heat shrinkage of the shrink wrapsleeving, in a length which extends distally beyond the sealing annulusof the fluid control device 25, and proximally beyond the sealingannulus of the filler valve 24, is sufficient to place a more or lessfluid-impervious coating over the bulb 21, whether the bag coupling 15is inside or outside the shrink wrap sleeve.

As the presently favoured method of placing the shrink wrap sleeve overthe catheter bulb 21, Applicant uses a vertically arranged heat shrinktunnel. Thus, the shaft 11 of the catheter is advanced through thesleeve prior to shrinking, so that the 90 mm length of the shrink sleevelies over the catheter bulb 21 in the axial position shown in FIG. 4 orFIG. 5, and then the catheter, with the sleeve in place, is placedbetween two vertical conveyor belts of the heat shrink tunnel, with theproximal end of the catheter uppermost. The conveyor belts advance thecatheter downwardly through the vertically arranged heat shrink tunneland, as the proximal end of the catheter passes through the tunnel, theheat within the tunnel will cause the sleeving to shrink around thecatheter bulb 21.

At the bottom end of the heat shrink tunnel, the catheter is taken fromthe conveyors, again to be subjected to a manual quality check beforebeing placed into a transport box for further processing.

FIG. 6 shows schematically the presently favoured method which applicantuses to insert the fluid control device 25 into the lumen of thecatheter. A plurality of long flexible fingers 50, themselves mounted attheir proximal ends to a finger ring 52, are introduced into the openend 22 of the catheter lumen which is to become the elastomeric bulb 21.Radially outward movement of the fingers 50 allows the plug 25 to beadvanced axially past the open end 22 of the lumen, and beyond the partof the lumen 21 which becomes the bulb, until the plug 25 reaches thepart 23 of the lumen which will become the distal neck of the bulb 21.Here, the lumen narrows down, over the length of a neck-in section R4 tothe diameter of the lumen in the shaft, which here is 0.8 mm.

This advancement of the plug 25 along the lumen 12 is accomplished by anengagement of a female end 54 of an engagement rod 56 arranged on theaxis of the plug insertion apparatus. The stem 27 of the plug 25 isreceived within the bore 58 of the female engagement portion 54 of theinjector rod 56.

Conveniently, the injector rod 56 is pneumatically operated. Inpractice, it is convenient to provide the apparatus with a foot pedalactuator for the injector rod 56, so that a human operative can arrangethe lumen end 22, fingers 50 and plug 25 as desired, with delicate useof the fingers, and then achieve plug insertion in the lumen 12 using amovement of the foot to actuate the foot pedal.

The rod 56 advances the plug 25 to the position shown in FIG. 7, inwhich it is snugly and co-operatingly abutting the neck-in section R4 ofthe lumen.

Once the plug is inserted, and the injector rod 56 retracted, thefingers 50 retract to their initial disposition, enabling the open end22 of the lumen 12 easily to be withdrawn from the fingers. The latexlumen wall is opaque, but because the prominent ring 26 d of the largediameter cylindrical portion of the plug 25 distorts the latex lumenwall, as can be seen in FIGS. 2, 3, 4 and 5, the operative can checkthat the plug 25 is in the desired location. It will be noted that thestem 27 projects proximally into the void within the bulb 21. After thischeck, the partially manufactured catheter can be placed in a transportbox, for onward transport and further processing.

It should be appreciated that the foregoing description of the inventionis intended merely to be illustrative and that other embodiments,modifications and equivalents may be apparent to those skilled in theart which may be within the literal or equivalent scope of the claims aspresented below or as they maybe broadened or narrowed by furtheramendment.

1. A drainage catheter, comprising: a body including a proximal end anda distal end; a drainage lumen extending between the body proximal endand the body distal end, including a distal fluid inflow port and aproximal fluid drain coupling; an inflation lumen extending between thebody proximal end and the body distal end, conveying inflating fluidfrom a proximal fluid supply element to a distal fluid acceptor balloon,the proximal fluid supply element adjacent the proximal fluid draincoupling; a polymeric control device positioned between the inflationlumen and the proximal fluid supply element, the control devicecomprising: a plug portion including a tapered outer surface and alumen; and a stem portion detachably connected to the plug portion, thestem portion closing a proximal opening of the lumen to prevent fluidfrom the proximal fluid supply element from entering the lumen; and asleeve secured about the proximal fluid supply element and the proximalfluid drain coupling to provide a fluid impervious coating.
 2. Thedrainage catheter according to claim 1, wherein the tapered portionincludes a first frusto-conical portion extending from a cylindricalportion connected to the stem portion, the cylindrical portion having adiameter larger than a largest diameter of the first frusto-conicalportion.
 3. The drainage catheter according to claim 2, wherein thetapered portion includes a second frusto-conical portion extending fromthe first frusto-conical portion, the second frusto-conical portionhaving a steeper taper than a taper of the first frusto-conical portion.4. The drainage catheter according to claim 2, wherein a length of thecylindrical portion is less than a radius of the cylindrical portion. 5.The drainage catheter according to claim 1, wherein a valve connected tothe proximal fluid supply element extends outside of the sleeve.
 6. Thedrainage catheter according to claim 1, wherein the proximal fluidsupply element is a bulb formed from an elastomeric material, and thesleeve is formed from a material more impervious to fluid than theelastomeric material.
 7. The drainage catheter according to claim 1,wherein the stem portion is integral to the plug portion, and detachablyconnected along a parting line.
 8. The drainage catheter according toclaim 1, wherein the stem portion is friction fitted to the stemportion.
 9. The drainage catheter according to claim 1, wherein thesleeve is shrink-wrapped about the proximal fluid drain coupling and theproximal fluid supply element.
 10. The drainage catheter according toclaim 9, wherein the sleeve includes a tear strip incorporated along itslength.
 11. A method of forming a drainage catheter, the drainagecatheter including a drainage lumen and an inflation lumen, theinflation lumen fluidly connecting a proximal fluid supply element anddistal balloon, a control device positioned between the inflation lumenand the proximal fluid supply element, the control device including astem portion detachably connected to a plug portion, the methodcomprising: introducing a dilation device into the proximal fluid supplyelement, the dilation device including a passage; dilating the proximalfluid supply element with the dilation device; coupling the stem portionof the control device to an injector rod; inserting the injector rodwith the coupled control device into the passage in the dilation device,and pushing the injector rod through the passage until the stem portionof the control device enters into a proximal end of the inflation lumen;decoupling the injector rod from the stem portion of the control deviceand retracting the injector rod; and removing the dilation device.